Rocks in a hydrocarbon reservoir store hydrocarbons (for example, petroleum, oil, gas, or any combinations thereof) by trapping the hydrocarbons within porous formations in the rocks. Permeability measures the ability of a fluid to flow through porous media such as reservoir rocks. The permeability of porous media is related to the porosity of porous media and to the quality of the porous media. Porosity is a measure of the void (empty) spaces in a material. Porosity is a fraction of the volume of voids over the total volume. Porosity is represented as a number between 0 and 1 or, as a percentage, between 0 and 100%. The quality of the porous media refers to the shapes of the pores in the porous media and their level of connectedness. The level of connectedness indicates whether the porous media is compartmentalized or networked. The compartmentalized porous media restricts the ability of a fluid to flow through it. The porous media that is networked through a matrix of connected pores may enable the fluid to flow through it. The permeability of a porous media sample taken from a reservoir indicates the ability of a hydrocarbon bearing formation to flow and produce hydrocarbon products in the reservoir.